Chili peppers have been a part of the human diet for thousands of years, but the origins of heat in foods and beverages is rooted in alliums, rhizomes, and peppercorns. A savvy food product developer knows that the source (or sources) of heat is only one part of the equation. There also needs to be the right complement of flavors.
Heat as a basic flavor note can be derived from multiple sources other than chili peppers, including ginger, cloves, horseradish (including wasabi), and even good old peppercorns (white, black, and green). But chili peppers — in their hundreds of sizes, shapes, varieties, and heat levels — still dominate.